U of I Department of Biology Professor Chris Marx has been awarded a $1.4 million grant from the Department of Energy to support his project “Converting methoxy groups on lignin-derived aromatics from a toxic hurdle to a useful resource: a systems-driven approach”. This project involves the Marx and Vasdekis labs here at University of Idaho, as well as the labs of Ceci Martinez-Gomez at U.C. Berkeley and Jeremy Draghi at Virginia Tech.
Lignin-derived compounds from plant biomass are highly abundant, usually 20-40% of plant biomass, but they are amongst the most recalcitrant for microbial conversion into valuable products like biofuels. Acid hydrolysis of lignin converts the polymer into a wide variety of aromatic molecules which are often toxic. Because many of these aromatic molecules also have methoxy groups that are released as formaldehyde during degradation, this creates a second major source of toxicity. In an earlier DOE-funded project, they discovered that some Methylobacterium strains grow exceptionally well on aromatics, and do not release formaldehyde into the medium from the methoxy groups while they do so. Given that we have recently discovered novel formaldehyde stress response systems in this organism, this represents a good chassis for biotechnological development.
Over the course of developing Methylobacterium extorquens into a model system for conversion of methoxylated aromatics, one fundamental challenge has been that genetically-identical populations of cells exhibit tremendous cell-to-cell variability in key phenotypes. There is significant heterogeneity in growth, viability, and metabolic processes. This led to the hypothesis that the physiological thresholds that lead to cell-to-cell variability within a single genetic strain will also exist for mutations or environmental variables that affect the same processes. As such, variability amongst cells is not just a challenge, in terms of the instability of growth and production, but may actually be an opportunity, providing information as to which aspects of cells can be manipulated to develop effective biotechnological processes from these difficult feedstocks.